[Switch Access] Update preview focus ring style

Per the bug filed by our UX designer, update the preview focus ring to
have a solid inner ring, and a dashed outer ring with 4dip dashes and
2dip gaps.

Since Switch Access is the only application of the DASHED focus ring
style currently, I modified that style directly, rather than creating
another new style.

Bug: 1152610
Change-Id: If61810ed594e7f388a8cbf71aaa41a44c2ed3cb6
AX-Relnotes: Dashed focus ring in Switch Access now has a different style.
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2622757Reviewed-by: David Tseng <dtseng@chromium.org>
Commit-Queue: Anastasia Helfinstein <anastasi@google.com>
Cr-Commit-Position: refs/heads/master@{#842610}

ash/accessibility/accessibility_focus_ring_layer.cc

@@ -23,8 +23,8 @@ namespace {
 // transparent.
 constexpr int kGradientWidth = 6;
 constexpr int kDefaultStrokeWidth = 2;
-constexpr float kDashLengthDip = 3.f;
-constexpr float kGapLengthDip = 5.f;
+constexpr float kDashLengthDip = 4.f;
+constexpr float kGapLengthDip = 2.f;
 
 int sign(int x) {
   return ((x > 0) ? 1 : (x == 0) ? 0 : -1);
@@ -182,23 +182,20 @@ void AccessibilityFocusRingLayer::DrawDashedFocusRing(
   SkPath path;
   gfx::Vector2d offset = layer()->bounds().OffsetFromOrigin();
 
+  flags.setColor(custom_color());
+  flags.setStrokeWidth(kDefaultStrokeWidth);
+
+  path = MakePath(ring_, 0, offset);
+  recorder.canvas()->DrawPath(path, flags);
+
   SkScalar intervals[] = {kDashLengthDip, kGapLengthDip};
   int intervals_length = 2;
   flags.setPathEffect(SkDashPathEffect::Make(intervals, intervals_length, 0));
-
-  // To keep the dashes properly lined up, we will draw the outside line first,
-  // and cover it with the inner line.
   flags.setColor(secondary_color_);
-  flags.setStrokeWidth(3 * kDefaultStrokeWidth);
 
-  path = MakePath(ring_, 0, offset);
+  path = MakePath(ring_, kDefaultStrokeWidth, offset);
   recorder.canvas()->DrawPath(path, flags);
 
-  flags.setColor(custom_color());
-  flags.setStrokeWidth(kDefaultStrokeWidth);
-
-  path = MakePath(ring_, 0, offset);
-  recorder.canvas()->DrawPath(path, flags);
 }
 
 void AccessibilityFocusRingLayer::DrawGlowFocusRing(ui::PaintRecorder& recorder,